Electrical measuring instrument.



No. 644,330. Patented Feb. 27, [900. i,

J. W. PACKARD.

ELECTRICAL MEASURING INSTRUMENT.

(Application filed. Jan. 12, 1900.)

(No Model.) 2 Sheets-Shet l.

J/a Wow j .THE "cams PETERS co. FNOTO-LIYHQ, wuumoron. u. c.

' Patented Feb. 27, I900. J. W. PACKARD.

ELECTRICAL MEASURING'INSTRUMENT. (No Model.)

(Applicatiofi filed Jan. 12, 1200.,

2 Sheets-Sheet 2.

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UNITED STATES PATENT OFFICE.

JAMES W. PA'cKARD, OF WARREN, OHIO.

. ELECTRICAL M EASURIN'G INSTRUMENT.

SPECIFICATION forming part of Letters Patent-NO 644,330, dated. February 27,1900. Application filed January 12. 1900. Serial No. 1,245. (He med al-) citizen of the United States, residing at War-- ren, in the county of Trumbull and State of Ohio, have invented certain new and useful 1 Improvements in Electrical Measuring In-' struments, of which the following is a specification. V I

This improved electrical measuring instrument is adapted for-the measurement of either current or potential and in a modified form it may be used to measure power-that is, it is adapted for use in its various forms as an ammeter, voltmeter, and wattmeter.

.Rgferring to the drawings, Figurel is a plan view of the instrument adapted for use as an ammeter or voltmeter. Fig. 2 is a front view of the same looking in the direction of the arrow 2, Fig. 1. Fig. 3 is a section on the line 3 3, Fig. 1. Fig. 4is adiagram illustrate ing a development of the coil in full lines and the pathof the core in dotted lines. Fig. 5 is a-view similar to Fig. 3, but showing the instrument adapted for use as a wattmeter 5 and Figs. 6 and 7 are views similar to Fig. 4, but illustrating modifications.

One object of the present invention is to produce a measuring instrument of simple construction which shall have a large range of movement and be sensitive throughout said movementto slight changes in current or potential.

. Another object is to produce an instrument in which, if desired, the scale may be divided into equal parts throughout, representing equal increments in current. or potential. In some cases it maybe desirable to have the instrument more sensitive at certain portions of the travel ofthe index than at other portions. This-may be accomplishedin my invention by very simple means, which willbe hereinafter described.

Referring to Figs. 1, 2, and 3 of the drawings, 10 indicatesa suitable base upon which the various parts of the device are mounted. (3n suitable supports 11 is carried a circular scale 12. Concentric withthe scale is an indicator-shaft 13, mounted in suitable bearings 14 15, the lower bearing being supported on the base and the upper bearingon the arm 16 of a standard or post 17. The shaft 1.3 carries a pointer or indicator 18,'Whichinthe other end 5 5 described I The solenoid A hasits coilfiattened, the

opposing walls 20 21 being'parallel and concentric with the shaft 13, as best shown in Fig. 1, the coil being bent sharply at 23 and 24. ,For convenience the parts 23-24 will be termedthe ends of the coil. As shown in Figs. 2 and 3, the coil is distorted vertically .I.

as well as horizontally, being arranged spirally about the indicator-shaft. The walls or branches 20 21 of the solenoid are arranged within the same angle as the scaleandfare ment with the scale, as shown in Fig. 1. In said figure. the coil and scale occupy nearly one hundred and eighty degrees; but they may measure more or less angularly, as de-' sired. The walls of the coil gradually rise from one end 24 to the opposite end 23, the increasein elevation being uniform for each degree of the scale. The indicator-shaft has an arm 25, upon which is mounted a core 26, said core in Figs. 1 to 3, inclusive, being in the form of a vertical plate adapted to travel in the space between the walls of the solenoid. The core normally stands at the lower end of the solenoid and as current is passed through the coil it tends to draw the core axi ally into it in accordance with a well-known law. It will be seen that the core can pass into the coil only by rotating about the indicator-shaft,-and1 the attractive force of 4 the coil is thus utilized to give the indicator: shaft a rotary :movement. The amount of rotation will vary with the force-of the cur rent passing through the coil and also withthe angularity of the coil inavertical plane. Each instrument can be nicely adjusted to its scaleby simply adjusting the angle of inclination of the coil. As shown, the coil is connected'to binding-posts 27 28.

In Fig. 4, 30 indicates thedevelopment o the coil in diagram, and 31 indicates the path of the core 26. figure that the horizontal component of the force of the solenoid tends to draw the core It will be evident from this to the right and that this horizontal component depends upon the inclination of the coils In the diagram Fig. 4 the solenoid 30. rises uniformly from end to end and the horizontal component developed by it is the same throughout the travel of the core 31. In some instances it is desirable that the units of the scale should be larger at one portionthan at anotherin order to indicate variations of current or potential with greater delicacy at a given portion of ascale. This may be accomplished by suitably varying the inclination of the solenoid. Thus, as shown in the diagram Fig. 6 the solenoid 30 is given greater inclination at its ends and less at its middle than the solenoid 30 in Fig. 4. This will "ause the index to travel more slowly toward the end of the solenoid and more rapidly at its middle portionfor a given increment in current or potential. In such case the scale should be varied accordingly, the units at the middle of the scale being longer than at its ends. In the diagram Fig. 7 this condition is reversed, the solenoid 30 having its'greatest inclination at the middle, which would render it necessary to make the units of the scale shorter at the middle than at the ends.

From the foregoing description it will be evident that I may arrange a scale for any special purpose having its units of equal or unequal length, as desired, by simply varying the inclination of the solenoid at different points. This is one of the valuable features of thepresent invention.

In Fig. 5 is shown an embodiment of the invention adapted for use as a wattmeter.

This device is the same as that illustrated in" Figs. 1 to 3, inclusive, with the exception that a small coil 32 is substituted for the core claim, and desire to secure by Letters Patent,

1. An electrical measuring instrument, comprising in combination a core adapted to revolve about an axis, andaflattened solenoid-' coil arranged spirally about said axis, said core standing normally at one end of the coil, and being adapted to move toward the other end of the coil under the influence of said solenoid when energized.

2. An electrical measuring instrument, comprising in combination a scale, an indicator, an indicator-shaft, means for normally holding the indicator at zero on the scale, a solenoid-core carried by said indicator-shaft, and a solenoid having a flattened coil, the opposite walls of said coil being circular and concentric with the indicator-shaft and inclined to a plane at right angles to said shaft, said core being adapted to travel between the walls of the coil, for the purpose set forth.

3. An electrical measuring instrument, comprising in'combination a scale, an indicator,

an indicator-shaft, a flattened solenoid-coil ar-- ranged spirally about said shaft, and a shuntcoil carried by said shaft and adapted to travel between the walls of the solenoid-coil, for the purpose set forth.

4. An electrical measuring instrument, coniprisiug, in combination, a scale, an indicator, an indicator-shaft, a solenoid-core carried by said indicator-shaft, and a solenoid having a flattened coil, the opposite walls of said coil being circular and concentric with the indicator-shaft, said coil being variably inclined with reference to a plane at right angles to said shaft whereby said core is caused to travel variable distances for equal increments of current or potential. I I

In testimony whereof I affix my signature in presence of two witnesses.

JAMES W. PACKARD.

Witnesses: l

ROBT. E. GoRToN, M. S. ANDREWS. 

